1. Field of the Invention
The present invention relates to a method for producing alkylphenol, and more particularly, to a method for producing alkylphenol by reactive distillation.
2. Description of Related Art
Alkylated aromatic compounds have several important commercial values. For example, nonylphenol is mainly used to produce nonylphenol polyethoxylates for use as non-ionic surfactants, and can be used as cleansing agents and emulsifiers. Nonylphenol can also be used in the productions of pulp, paint, adhesive agents, leather products, rubber and plastics.
The chemical reactions involving alkylation of aromatic compounds with olefinic compounds have been studied for a long time. Traditionally, phenol and an olefinic compound are charged into a fixed-bed reactor or a stirring reactor for a reaction. However, the temperature is high due to the exothermic reaction; therefore, heat energy needs to be removed from the reactor or the outlet of reactants. Furthermore, the generation of byproducts easily blocks the pores of a catalyst, such that the catalytic activity is decreased. Generally, the charging of an excessive amount of phenol into a reactor is needed to reduce the generation of byproducts, but the energy consumed for subsequent recycling of phenol is increased.
Recently, reactive distillation is also employed to produce an alkylated aromatic compound. For example, CN100337998C discloses the production of alkylated aromatic hydrocarbon by a continuous pressurized reactive distillation process. However, the process still requires a high molar ratio of aromatic hydrocarbon to olefine.
Accordingly, there still exists a need for a method to produce alkylphenol, while still simplifying the steps and saving the energy consumed during the method.